Semiconductor device, packaging method thereof, and package product thereof

ABSTRACT

A semiconductor device includes: a circuit constituting section having (a) a function circuit and (b) an externally-drawing electrode, connected to the function circuit, on a surface of the circuit constituting section; and an insulating layer provided on a side of a rear surface of the circuit constituting section, wherein the insulating layer has a face opposite to the circuit constituting section, and an area of the face is set so as to be larger than an area of the rear surface of the circuit constituting section. Thus, it is possible to clear such problems that an adhesive that has overflowed from a space between the semiconductor device and the circuit substrate adheres to a bonding collet when flip chip bonding is performed.

FIELD OF THE INVENTION

[0001] The present invention relates to a semiconductor device,particularly to (a) a semiconductor device suitable to manufacture athin semiconductor package, (b) a packaging method thereof, and (c) apackage product thereof.

BACKGROUND OF THE INVENTION

[0002] Recently, with miniaturization of electric devices, circuitsubstrates have been made thin. In order to package parts in acomplicated and narrow space inside a small electric device (smallportable device) in a high-density manner, flexible printed circuits(FPC) which can be bent have been used. Further, a technique, in which acircuit pattern is formed on a box body itself so as to realize a smallbody and a light weight, is proposed.

[0003] Under such condition, in a case where a typical semiconductorpackage, for example, a semiconductor package of a resin-sealing typerepresented by QFP (Quad Flat Package), BGA (Ball Grid Allay), and CSP(Chip Scale Package) is used in a small portable device in particular,there occurs the following problems.

[0004] That is, even though a thin substrate or a flexible printedsubstrate can be bent (transformed) so that its shape is complicated inthe small portable device, it is impossible to bend a typicalsemiconductor package due to its hardness. This means that: asemiconductor device which cannot be transformed is provided on aflexible printed substrate which can be bent freely, so that it becomesdifficult to mount the substrate in a space having a complicated shapeinside the small portable device.

[0005] It is also difficult to mount a hard semiconductor package on acircuit formed on a curved surface of a box body.

[0006] In order to solve the problems, Japanese Unexamined PatentPublication No. 64379/1994 (Tokukaihei 6-64379)(Publication date: Mar.8, 1994) and Japanese Unexamined Patent Publication No. 11129/2000(Tokukai 2000-11129)(Publication date: Jan. 14, 2000), for example,recite such a technique that: a semiconductor device (hereinbelowreferred to as semiconductor chip) is made thin so as to be flexible,thus bringing about no problem in bending.

[0007] Typically, flip chip bonding is performed upon electricallyconnecting a semiconductor chip to a circuit substrate so as to make athickness of whole the semiconductor chip thin. This is based on thefollowing reason. In a case where wire bonding is performed uponelectrically connecting the semiconductor device to the circuitsubstrate, it is necessary to coat a wire with an epoxy resin etc. forprotection, which causes the semiconductor package to be thick, so thatit becomes difficult to bend the semiconductor package.

[0008] In a case where the semiconductor chip and the circuit substrateare connected to each other in accordance with the flip chip bonding forexample, a protruding electrode formed on an externally-drawingelectrode of the semiconductor chip is positioned corresponding to anelectrode on the circuit substrate, and is pressed so that theprotruding electrode and the electrode on the circuit substrate are incontact with each other, and an adhesive resin is cured. This enablesthe semiconductor chip to be packaged on the circuit substrate inaccordance with the flip chip bonding, so that a thin semiconductorpackage is formed.

[0009] Note that, as to the foregoing publications, Japanese UnexaminedPatent Publication No. 11129/2000 (Tokukai 2000-11129)(Publication date:Jan. 14, 2000) discloses an example in which a semiconductor chip ispackaged on a circuit substrate via an anisotropic conductive sheet inaccordance with the flip chip bonding.

[0010] Since a semiconductor package manufactured in this manner has anextremely thin semiconductor chip compared with a typical semiconductorpackage, it is possible to make the semiconductor package itself thin,so that the semiconductor package can be curved. Thus, it is possible toprovide the semiconductor package on a curved surface of a narrow spacein a box body etc.

[0011] Further, when a thickness of the semiconductor chip is set to benot more than 100 μm so as to make the semiconductor package thin, thesemiconductor chip tends to be damaged. Thus, it is difficult to treatthe semiconductor chip in transporting the semiconductor chip or inpackaging the semiconductor chip in the circuit substrate, so that thereoccurs such a problem that the productivity is led to worse.

[0012] Then, the following technique is proposed: a thick reinforcingmember is temporarily formed on a side of a rear surface of thesemiconductor chip so as to perform the flip chip bonding, and thereinforcing member is removed after performing the flip chip bonding, sothat it becomes easier to treat the semiconductor chip which tends to bedamaged in making the semiconductor chip thin.

[0013] Incidentally, in a case where the semiconductor chip and thecircuit substrate are connected to each other in accordance with theflip chip bonding, it is typically required to use a thermally curableadhesive, represented by ACF (anisotropic conductive adhesive film) andACP (anisotropic conductive adhesive paste), which softens or flows atleast upon performing the flip chip bonding.

[0014] However, in a case where the foregoing thin semiconductor chip isconnected to the circuit substrate in accordance with the flip chipbonding using the foregoing adhesive, there occur the followingproblems.

[0015] In typical flip chip bonding, as shown in FIG. 7, a semiconductorchip 101 is temporarily subjected to a pressure via a thermally curableadhesive 107 such as ACF on a circuit substrate 105 so that electrodesof the semiconductor chip 101 and electrodes of the circuit substrate105 are electrically connected to each other. Under this condition, abonding collet 110 presses the semiconductor chip 101 against thecircuit substrate 105.

[0016] Thus, when the bonding collet adds a pressure, that is, when thebonding is performed, the heated adhesive 107 softens or flows due tothe heat so as to overflows from a space between the semiconductor chip101 and the circuit substrate 105, so that the heated adhesive 107 isinclined to surround a side face of the semiconductor chip 101.

[0017] Thus, as shown in FIG. 7, in a case where the boding colletpresses the semiconductor chip 101 directly, there is a possibility thatthe overflowing adhesive 107 adheres to the bonding collet 110.

[0018] Further, as shown in FIG. 8, in a case where there is provided areinforcing member 108 on the semiconductor chip 101, the adhesive 107does not adhere to the bonding collet 110 depending on a thickness ofthe reinforcing member 108, but there is a possibility that the adhesive107 adheres to the reinforcing member 107.

[0019] That is, as shown in FIG. 7, in the case where the adhesive 107reaches the bonding collet 110, the bonding collet 110 is stuck on thesemiconductor chip 101, so that it is difficult to perform the flip chipbonding successively without any problem.

[0020] Further, as shown in FIG. 8, in the case where the adhesive 107reaches the reinforcing member 108, it is difficult to remove thereinforcing member 108 after packaging the semiconductor chip 101 on thecircuit substrate 105.

[0021] Thus, in a case of using an adhesive which softens or flows uponperforming the flip chip bonding so as to connect the semiconductor chipto the circuit substrate, there occurs such a problem that theproductivity of the semiconductor package is led to worse.

[0022] Further, as shown in FIG. 8, the method in which the reinforcingmember is formed on the semiconductor chip requires (a) a step of addingthe reinforcing member to the semiconductor chip and (b) a step ofremoving the reinforcing member from the semiconductor chip packaged onthe circuit substrate, so that the number of steps required inmanufacturing the semiconductor package is increased. This also bringsabout such a problem that the productivity of the semiconductor packageis led to worse.

SUMMARY OF THE INVENTION

[0023] The present invention is made so as to solve the foregoingproblems. The object of the present invention is to provide (a) asemiconductor device which does not lead the productivity of asemiconductor package to worse in a case of using an adhesive whichsoftens or flows upon performing flip chip bonding with respect to asemiconductor chip and a circuit substrate, and (b) a packaging methodof the semiconductor device.

[0024] In order to solve the foregoing problems, a semiconductor deviceof the present invention includes: a circuit constituting section having(a) a function circuit and (b) an externally-drawing electrode,connected to the function circuit, on a surface of the circuitconstituting section; and an insulating layer provided on a side of arear surface of the circuit constituting section, wherein the insulatinglayer has a face opposite to the circuit constituting section, and anarea of the face is set so as to be larger than an area of the rearsurface of the circuit constituting section.

[0025] Typically, in a case of using an adhesive, represented by ACF(anisotropic conductive film) and ACP (anisotropic conductive paste),which softens or flows at least upon performing the flip chip bonding,so as to perform the flip chip bonding with respect to the semiconductordevice and a circuit substrate, there is a possibility that: theadhesive provided on the circuit substrate flows upon performing theflip chip bonding so as to be let out to the outside of thesemiconductor device, and the overflowing adhesive surrounds a side faceof the circuit constituting section so as to reach a rear surface of thecircuit constituting section. As a thickness of the circuit constitutingsection becomes thinner, the overflowing adhesive is more likely toreach the rear surface of the semiconductor device.

[0026] Then, like the foregoing arrangement, the insulating layer isformed on the side of the rear surface of the circuit constitutingsection. In the insulating layer, an area of the face opposite to thecircuit constituting section is set to be larger than an area of thecircuit constituting section, so that the adhesive that has overflowedfrom a space between the semiconductor device and the circuit substrateupon performing the flip chip bonding is dammed by the insulating layereven though the adhesive surrounds the side face of the circuitconstituting section.

[0027] Thus, since the overflowing adhesive does not adhere to thebonding collet for pressing the semiconductor device via the insulatinglayer when the flip chip bonding is performed, it is possible to reduceoccurrence of such problem that the semiconductor device adheres to thebonding collet due to the overflowing adhesive, so that it is possibleto continue the flip chip bonding without any problem.

[0028] Thus, it is possible to improve the productivity of thesemiconductor package as a package product obtained by packaging thesemiconductor device on the circuit substrate.

[0029] For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030]FIG. 1 is a schematic sectional view of a semiconductor device ofthe present invention.

[0031]FIG. 2 is a schematic sectional view of a semiconductor package inwhich the semiconductor device shown in FIG. 1 is packaged on a circuitsubstrate.

[0032]FIG. 3(a) is a schematic sectional view showing a manufacturingprocess of the semiconductor device shown in FIG. 1.

[0033]FIG. 3(b) is a schematic sectional view showing a manufacturingprocess of the semiconductor device shown in FIG. 1.

[0034]FIG. 4(a) is a schematic sectional view showing a packagingprocess in which the semiconductor device manufactured in accordancewith the manufacturing processes shown in FIG. 3(a) and FIG. 3(b) ispackaged on the circuit substrate.

[0035]FIG. 4(b) is a schematic sectional view showing a packagingprocess in which the semiconductor device manufactured in accordancewith the manufacturing processes shown in FIG. 3(a) and FIG. 3(b) ispackaged on the circuit substrate.

[0036]FIG. 4(c) is a schematic sectional view showing a packagingprocess in which the semiconductor device manufactured in accordancewith the manufacturing processes shown in FIG. 3(a) and FIG. 3(b) ispackaged on the circuit substrate.

[0037]FIG. 5(a) is a schematic sectional view showing a packagingprocess in which a semiconductor device according to another embodimentof the present invention is packaged on the circuit substrate.

[0038]FIG. 5(b) is a schematic sectional view showing a packagingprocess in which the semiconductor device according to anotherembodiment of the present invention is packaged on the circuitsubstrate.

[0039]FIG. 6(a) is a schematic sectional view showing a packagingprocess in which a semiconductor device according to still anotherembodiment of the present invention is packaged on the circuitsubstrate.

[0040]FIG. 6(b) is a schematic sectional view showing a packagingprocess in which the semiconductor device according to still anotherembodiment of the present invention is packaged on the circuitsubstrate.

[0041]FIG. 6(c) is a schematic sectional view showing a packagingprocess in which the semiconductor device according to still anotherembodiment of the present invention is packaged on the circuitsubstrate.

[0042]FIG. 7 is a schematic sectional view showing a typical packagingprocess in which a semiconductor device is packaged on a circuitsubstrate.

[0043]FIG. 8 is a schematic sectional view showing another example of atypical packaging process in which a semiconductor device is packaged ona circuit substrate.

DESCRIPTION OF THE EMBODIMENTS

[0044] [Embodiment 1]

[0045] One embodiment of the present invention is described as follows.

[0046] A semiconductor device according to the present embodiment isarranged so that: as shown in FIG. 1, on a surface 1 a, there areprovided a function circuit and a protruding electrode 4 which is anexternally-drawing electrode connected to the function circuit, and acircuit constituting section 1 having the surface 1 a also has a rearsurface 1 b, and the rear surface 1 b is in contact with an insulatinglayer 2.

[0047] There is formed an Si substrate (silicon substrate) 3, whosesurface is as large as that of the insulating layer 2, on a face (rearsurface 2 b) which is the back with respect to a face (surface 2 a)opposite to the circuit constituting section 1 of the insulating layer2. Note that, the Si substrate 3 is removed after the semiconductordevice is packaged on a circuit substrate 5 described later.

[0048] An area of the surface 2 a of the insulating layer 2 is set to belarger than an area of the rear surface 1 b of the circuit constitutingsection 1.

[0049] Here, the area of the surface 2 a of the insulating layer 2 isdescribed as follows referring to FIG. 2. FIG. 2 shows how thesemiconductor device of the foregoing arrangement is packaged on thecircuit substrate 5, that is, FIG. 2 is a schematic sectional view of apackage product (semiconductor package).

[0050] As shown in FIG. 2, in the case where the semiconductor device ispackaged on the circuit substrate, the semiconductor device and thecircuit substrate 5 are provided so as to be opposite to each other sothat the protruding electrode 4 provided on the surface 1 a of thecircuit constituting section 1 is electrically connected to an electrode6 provided on a surface 5 a of the circuit substrate 5. Thesemiconductor device and the circuit substrate 5 are connected to eachother with the adhesive 7, such as ACF (Anisotropic Conductive Film),made of thermally curable resin.

[0051] In connecting the semiconductor device and the circuit substrate5 to each other, the flip chip bonding is performed, and a pressure andheat are added upon connection. Thus, the adhesive 7 softens and flowsso as to overflows outward from a connection portion between the circuitconstituting section 1 of the semiconductor device and the circuitsubstrate 5. At this time, it is necessary to dam an overflowing portion7 a of the adhesive 7 that has overflowed from the connection portion sothat the overflowing portion 7 a does not flow beyond the rear surface 1b of the circuit constituting section 1 and does not reach the rearsurface of the semiconductor device.

[0052] Thus, it is preferable that at least an area of the surface 2 aof the insulating layer 2, as shown in FIG. 2, is set to be so large asto be able to dam the adhesive 7, that has overflowed from theconnection portion upon performing the flip chip bonding, in a casewhere the adhesive 7 reaches the surface 2 a of the insulating layer 2.

[0053] In the present embodiment, description is given on asemiconductor device arranged so that: as shown in FIG. 1, there isformed the Si substrate 3 on the rear surface 2 b of the insulatinglayer 2, and there is formed the circuit constituting section 1 on thesurface 2 a of the insulating layer 2. That is, description is given onan SOI-type semiconductor device arranged so that there is formed thecircuit constituting section 1 on an SOI (Silicon on Insulator) wafer.

[0054] Further, since there is formed the protruding electrode 4, whichprotrudes outward, on the surface la of the circuit constituting section1, it is possible to readily connect the circuit substrate 5 (flexiblesubstrate) to the electrode 6 without fail.

[0055] A manufacturing process of the SOI-type semiconductor device isdescribed as follows referring to FIGS. 3(a) and 3(b), and FIGS. 4(a) to4(c).

[0056] First, as shown in FIG. 3(a), on the insulating layer 2 formed onthe Si substrate, there are provided a plurality of circuit constitutingsections 1 having function circuits.

[0057] As to a thickness of the circuit constituting section 1,approximately 0.5 μm to 100 μm thickness is required to arrange circuitsas a semiconductor device. It is preferable to set the thickness to benot more than 10 μm so as to secure the strength with respect to curvingof the semiconductor device. Note that, in the present embodiment, thethickness is set to be 3 μm.

[0058] In forming the insulating layer 2, it is possible to use an oxidefilm such as SiO₂ or a nitride film such as SiN. Note that, in thepresent embodiment, an SiO₂ film having a 0.1 μm thickness is used asthe insulating layer 2. The insulating layer 2 functions as a stopper inremoving the Si substrate 3 in accordance with etching in a latterprocess.

[0059] When a total thickness of the circuit constituting section 1 andthe insulating layer 2 is not more than 100 μm, the strength is notsufficient and it is difficult to treat the semiconductor device, sothat the thickness of the Si substrate 3 is set to be 400 μm.

[0060] The circuit substrate 5 is a flexible substrate, made ofpolyimide resin, which has a 10 to 25 μm thickness.

[0061] Next, as shown in FIG. 3(b), the protruding electrode 4 having anapproximately 3 to 5 μm height is formed on an active surface of thesemiconductor device, that is, on the externally-drawing electrodeformed on the function circuit of the surface 1 a of the circuitconstituting section 1.

[0062] The protruding electrode 4 is provided by forming nickel and goldsuccessively in accordance with electrolytic plating or electrolessplating.

[0063] The semiconductor device manufactured in this manner is cut so asto be divided into individual semiconductor devices in accordance with apredetermined dicing position.

[0064] Next, description is given on a manufacturing process of asemiconductor package in which the semiconductor device is packaged onthe circuit substrate 5.

[0065] First, as shown in FIG. 4 (a), an anisotropic-conductive-filmadhesive 7 is provided on the circuit substrate 5.

[0066] While, on the side of the Si substrate, the semiconductor deviceis subjected to vacuum absorption by the bonding collet 10, and theprotruding electrode 4 formed on the circuit constituting section 1 ofthe semiconductor device are positioned so as to correspond to theelectrode 6 on the circuit substrate 5. The bonding collet 10 performsthe vacuum absorption with respect to the semiconductor device by meansof a vacuum absorption hole 10 a formed in a central portion of thebonding collet 10.

[0067] Next, as shown in FIG. 4(b), the bonding collet 10 adds apressure so that the semiconductor device and the circuit substrate 5are in contact with each other, and heats them.

[0068] At this time, the adhesive 7 provided on a lower portion of thesemiconductor device softens and flows, and a part of the adhesive 7 islet out, so that an overflowing portion 7 a of the adhesive 7 reachesthe surface 2 a of the insulating layer 2 of the semiconductor device.

[0069] However, as described above, at least an area of the surface 2 aof the insulating layer 2, as shown in FIG. 2, is set to be so large asto be able to dam the overflowing adhesive 7 upon performing the flipchip bonding, in a case where the adhesive 7 reaches the surface 2 a ofthe insulating layer 2. Thus, it is possible to prevent the adhesive 7from adhering to the Si substrate 3 and the bonding collet 10, so thatthe flip chip packaging is completed without any problem.

[0070] Next, the Si substrate 3 is removed in accordance with etching.Thus, as shown in FIG. 4(c), the semiconductor package has such a shapethat the circuit constituting section 1 and the insulating layer 2 arepackaged on the circuit substrate 5 in accordance with the flip chippackage, so that it is possible to realize a flexible semiconductorpackage which can be bent in use. Note that, in a case where it is notnecessary to bend the semiconductor package and a thickness of the Sisubstrate 3 brings about no problem, it is not necessary to remove theSi substrate 3.

[0071] It is possible to perform the etching with respect to the Sisubstrate 3 by using solution in which fluorine and nitric acid aremixed for example.

[0072] In the present embodiment, a thickness of the circuitconstituting section 1 of the semiconductor device is thin such as notmore than 10 μm, which brings about the strength with respect tobending, so that the flexibility is realized. Thus, it is possible toprovide a semiconductor package which is so thin that the semiconductorpackage can be bent. Further, the insulating layer 2 may be removed withhydrofluoric acid.

[0073] [Embodiment 2]

[0074] Another embodiment of the present invention is described asfollows. Note that, the same reference signs are given to members havingthe same functions as the members of the foregoing embodiment, anddescription thereof is omitted.

[0075] A semiconductor device according to the present embodiment ismanufactured as in the embodiment 1. However, the semiconductor deviceaccording to the present embodiment is different from the semiconductordevice of the embodiment 1 in that, as shown in FIG. 5(a), a gold wirebump 14 is provided on the circuit constituting section 1 instead of theprotruding electrode 4, and in that ACP (Anisotropic Conductive Paste)adhesive 8 is used instead of the adhesive 7 made of ACF.

[0076] The gold wire bump 14 is provided on the circuit constitutingsection 1 by using a wire bonding technique, and its height is set to be50 to 60 μm.

[0077] Here, referring to FIGS. 5(a) and 5(b), description is given on amanufacturing process of a semiconductor package in which thesemiconductor device arranged in the foregoing manner is packaged on thecircuit substrate 5.

[0078] First, as shown in FIG. 5(a), by using a dispenser, the adhesive8 is provided on a predetermined position on the circuit substrate 5,that is, a position in the vicinity of a central portion of theconnection portion between the circuit constituting section 1 and thecircuit substrate 5.

[0079] While, the semiconductor device is subjected to absorption by thebonding collet 10, and the gold wire bump 14 of the semiconductor deviceis placed so as to correspond to the electrode 6 of the circuitsubstrate 5.

[0080] Further, when the bonding collet 10 adds a pressure so that thesemiconductor device and the circuit substrate 5 are in contact witheach other, the adhesive 8 spreads between the semiconductor device andthe circuit substrate 5, and a part of the adhesive 8 is let out, sothat an overflowing portion 8 a of the adhesive 8 reaches the surface 2a of the insulating layer 2 of the semiconductor device. Under thispressing condition, the connection portion is heated so as to cure theadhesive 8.

[0081] Next, the insulating layer 2 made of SiO₂ is removed inaccordance with etching. At this time, the Si substrate 3 is removedsimultaneously. Thus, it is possible to obtain a semiconductor packagein which only the circuit constituting section 1 as shown in FIG. 5(b)is connected to the circuit substrate 5 in accordance with the flip chipbonding.

[0082] Note that, in performing the etching with respect to the SiO₂,hydrofluoric acid is used.

[0083] In this manner, the semiconductor package has such a shape thatonly the circuit constituting section 1 of a thin semiconductor deviceis packaged on the circuit substrate 5 in accordance with the flip chippackaging, so that it is possible to realize a flexible semiconductorpackage which can be bent in use.

[0084] [Embodiment 3]

[0085] Another embodiment of the present invention is described asfollows. Note that, the same reference signs are given to members havingthe same functions as the members of the foregoing embodiment, anddescription thereof is omitted.

[0086] A semiconductor device according to the present embodiment ismanufactured as in the embodiment 1. However, the semiconductor deviceaccording to the present embodiment is different from the semiconductordevice of the embodiment 1 in that, as shown in FIG. 6(a), a solder bump24 is provided on the circuit constituting section 1 instead of theprotruding electrode 4, and in that an adhesive 9 made ofthermally-curable resin in liquid form is used instead of the adhesive 7made of ACF.

[0087] The solder bump 24 is provided on the circuit constitutingsection 1 in accordance with electrolysis plating, and its height is setto be approximately 80 μm.

[0088] Here, referring to FIGS. 6(a) and 6(b), description is given on amanufacturing process of a semiconductor package in which thesemiconductor device arranged in the foregoing manner is packaged on thecircuit substrate 5.

[0089] First, as shown in FIG. 6(a), the adhesive 9 is provided on apredetermined position on the circuit substrate 5, that is, a positionin the vicinity of a central portion of the connection portion betweenthe circuit constituting section 1 and the circuit substrate 5.

[0090] While, the semiconductor device is subjected to absorption bymeans of the bonding collet 10, and the solder bump 24 of thesemiconductor device is placed so as to correspond to the electrode 6 ofthe circuit substrate 5.

[0091] Further, when the bonding collet 10 adds a pressure so that thesemiconductor device and the circuit substrate 5 are in contact witheach other, the adhesive 9 spreads between the semiconductor device andthe circuit substrate 5 as shown in FIG. 6(b), and a part of theadhesive 9 is let out, so that an overflowing portion 9 a of theadhesive 9 reaches the surface 2 a of the insulating layer 2 of thesemiconductor device.

[0092] Under this pressing condition, the circuit substrate 5 is putinto a reflow oven so that the solder bump 24 melts so as to spread tothe electrode 6 of the circuit substrate 5. At this time, the adhesive 9is cured by the heat.

[0093] Next, the insulating layer 2 made of SiO₂ is removed inaccordance with etching. At this time, the Si substrate 3 is removedsimultaneously. Thus, it is possible to obtain a semiconductor packagein which only the circuit constituting section 1 as shown in FIG. 6(c)is connected to the circuit substrate 5 in accordance with the flip chipbonding.

[0094] Note that, in performing the etching with respect to the SiO₂,hydrofluoric acid is used.

[0095] In this manner, the semiconductor package has such a shape thatonly the circuit constituting section 1 of a thin semiconductor deviceis packaged on the circuit substrate 5 in accordance with the flip chippackaging, so that it is possible to realize a flexible semiconductorpackage which can be bent in use.

[0096] As described above, according to the present invention, since itis possible to package a semiconductor device so that an extremely thinsemiconductor circuit constituting section is reinforced with the Sisubstrate, it is possible to treat a semiconductor chip without damagingthe semiconductor chip.

[0097] Further, it is possible to realize flip chip packaging performedby using the adhesive such as ACF and ACP which softens and flows uponconnection, so that it is possible to provide a flexible semiconductorpackage which can be bent.

[0098] An area of the insulating layer of the semiconductor device isset so that the adhesive used upon connecting the circuit constitutingsection via the drawing electrode to the circuit substrate in accordancewith the flip chip bonding does not overflows from the insulating layerafter overflowing from the connection portion between the circuitconstituting section and the circuit substrate.

[0099] In this case, it is possible to dam the adhesive, which hadoverflowed from a space between the semiconductor device and the circuitsubstrate, by means of the insulating layer without fail, so that theadhesive does not reach a rear surface of the semiconductor device, thatis, a face with which the bonding collet etc. is in contact.

[0100] Thus, the adhesive which had overflowed does not adhere tomembers such as the bonding collet which are required in the flip chipbonding, so that it is possible to obtain such an effect that theproductivity of the semiconductor package can be improved.

[0101] Further, the insulating layer may be provided on a siliconsubstrate whose area is as large as that of the insulating layer.

[0102] In this case, the insulating layer is provided on a siliconsubstrate whose area is as large as that of the insulating layer, sothat the insulating layer is subjected to the flip chip bonding with ithaving the silicon substrate. Thus, even in a case where the circuitconstituting section is so thin as to tend to be damaged, the siliconsubstrate functions as a reinforcing substrate, so that it is possibleto provide such a semiconductor device that: the strength of thesemiconductor device can be secured so as to prevent it from beingdamaged, and it is easy to treat the semiconductor device with ease.

[0103] The externally-drawing electrode may be a protruding electrodewhich protrudes toward the circuit substrate in a case where theexternally-drawing electrode is made of any one of nickel, gold, andsolder, and the circuit constituting section is opposite to the circuitsubstrate.

[0104] In this case, the protruding electrode is formed on a surface ofthe circuit constituting section of the semiconductor device, so that itbecomes possible to perform the flip chip bonding easily and withoutfail. Further, the electrode is made of any one of nickel, gold, andsolder, so that it is possible to obtain suitable conductivity afterperforming the flip chip bonding.

[0105] A thickness of the circuit constituting section may be 0.5 μm to100 μm.

[0106] In this case, the thickness of the semiconductor layer having thecircuit constituting section is set to 0.5 μm to 100 μm, so that thesemiconductor device has the strength with respect to bending so as tohave the flexibility. Thus, it is possible to provide a thinsemiconductor package which can be bent.

[0107] The invention being thus described, it will be obvious that thesame way may be varied in many ways. Such variations are not to beregarded as a departure from the spirit and scope of the invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

What is claimed is:
 1. A semiconductor device comprising: a circuitconstituting section having (a) a function circuit and (b) anexternally-drawing electrode, connected to the function circuit, on asurface of the circuit constituting section; and an insulating layerprovided on a side of a rear surface of the circuit constitutingsection, wherein the insulating layer has a face opposite to the circuitconstituting section, and an area of the face is set so as to be largerthan an area of the rear surface of the circuit constituting section. 2.The semiconductor device as set forth in claim 1, wherein in theinsulating layer, the area of the face opposite to the circuitconstituting section is set so that an adhesive, used upon connectingthe circuit constituting section via the externally-drawing electrode toa circuit substrate in accordance with flip chip bonding, does notoverflow from the insulating layer after overflowing from a connectionportion between the circuit constituting section and the circuitsubstrate.
 3. The semiconductor device as set forth in claim 1, furthercomprising a silicon substrate, wherein the insulating layer is providedon the silicon substrate.
 4. The semiconductor device as set forth inclaim 1, wherein the externally-drawing electrode is made of any one ofnickel, gold, and solder, and the externally-drawing electrode is aprotruding electrode that protrudes toward the circuit substrate whenthe circuit constituting section is opposite to the circuit substrate.5. The semiconductor device as set forth in claim 1, wherein a thicknessof the circuit constituting section is 0.5 μm to 10 μm.
 6. A packagingmethod of a semiconductor device, the semiconductor device including: acircuit constituting section having (a) a function circuit and (b) anexternally-drawing electrode, connected to the function circuit, on asurface of the circuit constituting section; and an insulating layerprovided on a side of a rear surface of the circuit constitutingsection, wherein: the insulating layer has a face opposite to thecircuit constituting section, and an area of the face is set so as to belarger than an area of the rear surface of the circuit constitutingsection, the method comprising the step of packaging the semiconductordevice on a circuit substrate by using an adhesive in accordance withflip chip bonding.
 7. A packaging method of a semiconductor device, thesemiconductor device including: a circuit constituting section having(a) a function circuit and (b) an externally-drawing electrode,connected to the function circuit, on a surface of the circuitconstituting section; and an insulating layer provided on a side of arear surface of the circuit constituting section, wherein: theinsulating layer has a face opposite to the circuit constitutingsection, and an area of the face is set so as to be larger than an areaof the rear surface of the circuit constituting section, and theinsulating layer is provided on a silicon substrate, the methodcomprising the steps of: performing flip chip bonding with respect tothe semiconductor device and a circuit substrate by using an adhesive;and removing the silicon substrate of the semiconductor device.
 8. Themethod as set forth in claim 6, further comprising the step of removingthe insulating layer of the semiconductor device.
 9. The method as setforth in claim 7, further comprising the step of removing the insulatinglayer of the semiconductor device.
 10. The method as set forth in claim6, wherein a thickness of the circuit constituting section is 0.5 μm to100 μm.
 11. The method as set forth in claim 7, wherein a thickness ofthe circuit constituting section is 0.5 μm to 100 μm.
 12. The method asset forth in claim 6, wherein the adhesive is a liquid type or film typeadhesive having anisotropic conductivity.
 13. The method as set forth inclaim 7, wherein the adhesive is a liquid type or film type adhesivehaving anisotropic conductivity.
 14. A package product obtained inaccordance with a packaging method of a semiconductor device, thesemiconductor device including: a circuit constituting section having(a) a function circuit and (b) an externally-drawing electrode,connected to the function circuit, on a surface of the circuitconstituting section; and an insulating layer provided on a side of arear surface of the circuit constituting section, wherein: theinsulating layer has a face opposite to the circuit constitutingsection, and an area of the face is set so as to be larger than an areaof the rear surface of the circuit constituting section, the methodcomprising the step of packaging the semiconductor device on a circuitsubstrate by using an adhesive in accordance with flip chip bonding. 15.A package product obtained in accordance with a packaging method of asemiconductor device, the semiconductor device including: a circuitconstituting section having (a) a function circuit and (b) anexternally-drawing electrode, connected to the function circuit, on asurface of the circuit constituting section; and an insulating layerprovided on a side of a rear surface of the circuit constitutingsection, wherein: the insulating layer has a face opposite to thecircuit constituting section, and an area of the face is set so as to belarger than an area of the rear surface of the circuit constitutingsection, the insulating layer being provided on a silicone substrate,the method comprising the steps of: performing flip chip bonding withrespect to the semiconductor device and a circuit substrate by using anadhesive; and removing the silicon substrate of the semiconductordevice.